SQL injection inside Microsoft-signed system stored procedures is not supposed to happen. Yet, as I’ve been documenting in this series, it happens more often than you may assume.
This article walks through another one I found and reported to the Microsoft Security Response Center (MSRC). It’s a textbook SQL injection sitting inside sys.sp_MSdeletefoldercontents, a system stored procedure used by SQL Server replication.
What makes it interesting is not the injection technique itself (there is no clever Unicode trick this time), but what it enables: a working execution path for xp_cmdshell on a server where xp_cmdshell is explicitly disabled by

